Inserter systems, such as those applicable for use with the present invention, are mail processing machines typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Examples of such inserter systems are the 8 series, 9 series, and APS™ inserter systems available from Pitney Bowes Inc. of Stamford, Conn.
In many respects, the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. Then, a variety of modules or workstations in the inserter system work cooperatively to process the sheets until a finished mail piece is produced. The exact configuration of each inserter system depends upon the needs of each particular customer or installation.
Typically, inserter systems prepare mail pieces by gathering collations of documents on a conveyor. The collations are then transported on the conveyor to an insertion station where they are automatically stuffed into envelopes. After being stuffed with the collations, the envelopes are removed from the insertion station for further processing. Such further processing may include automated closing and sealing the envelope flap, weighing the envelope, applying postage to the envelope, and finally sorting and stacking the envelopes.
One problem that arises with high speed mail processing machines is jamming. When a jam occurs, not only is there potential for the jammed piece to be damaged, but also collateral damage from moving pieces that may crash into the jammed mail pieces, or that may otherwise be forced to come to a sudden halt. In order to minimize damage, it is known to shut down the mail processing machine upon the occurrence of a jam to minimize collateral damage, and so that the jam can be cleared.
One complication is that some transports, by their nature, cannot be shut down while documents are still under their control. One example, is a Pitney Bowes R150 postage meter mailing machine that prints postage indicia. For the integrity of the postage printing process, an R150 mailing machine is not shut down while envelopes are within its control. Accordingly, if a jam occurs anywhere downstream of the R150 mailing machine, then envelopes within the mailing machine at the time may become collaterally damaged when they are suddenly halted downstream of the R150 mailing machine transport system.
For purposes of this description, the term “non-staging transport” refers to a transport, such as in the R150 mailing machine, that continues to run, even after a jam has been detected. It will be understood by one skilled in the art that there are also other examples of non-staging transports used elsewhere, whereby transport rollers and belts run continuously regardless of whether there is a jam, or whether documents are currently being processed.
Thus, stated more generically, in a mail processing machine where one or more of the upstream modules are non-staging, a problem arises when there is a jam downstream. Because the upstream mailpieces are conveyed by a transport that cannot stage mailpieces, the downstream transport mechanism must continue to accept the mailpieces before the non-staging transport is caused to stop in order to avoid a second jam. In the past, when a jam occurs, the transport mechanism downstream of the non-staging area is stopped as soon as the last mailpiece leaves the non-staging area. This results in the pile up of some mailpieces in the jam area, or in a portion of the transport that has halted as a result of the jam. However, before the downstream transport is stopped, not all of the received mailpieces can be staged in a normal manner, some of them end up at the jam location. Such a pile up may cause collateral damage.